The passenger comfort of human-bus-road coupled vibration due to different sitting positions

The road surface roughness and the dynamic interaction between vehicle and asphalt road are the main reasons causing the decline of passengers' comfort. Asphalt road model with interlayer contact and 13-degree-of-freedom bus-human model were established using finite element method and dynamic equilibrium theory. The road roughness and random traffic were incorporated to analyze the dynamic responses of bus and human body due to the human-bus-road coupled vibration. In addition to the ISO2631 evaluation standard in time domain, the randomness and ambiguity of human perception to vibration were considered, and the annoyance rate as a quantitative index for evaluating passengers' comfort was proposed. For the evaluation in frequency domain, the resonance perspective, psychological and physiological aspects of human were taken into consideration. The effects of different seat positions on the dynamic responses of human body were also analyzed. The results indicate that the diverse seat positions have some effects on comfort, that is, the passengers in middle rows have the lowest annoyance rate and highest comfort, while those in rear rows have the highest annoyance rate and lowest comfort. There is no obvious trend on the vibration frequency of passengers in different conditions, however, it could be useful for the bus developers.